1. Field of the Invention
The present invention is directed to an automated rule based process control method and apparatus that includes feedback and, more particularly, to a system in which rules concerning the operation of a process are inferred from data samples of the process being controlled, the rules are used to move the process toward the desired goal and as the process operates new data samples allow the inference of new rules, so that the process is automatically optimized and the rules for controlling the process are automatically generated.
2. Description of the Related Art
Process control when attempting to optimize toward a desired goal has, been characterized by statistical analysis methods which analyze the behavior of a process and attempt to predict process behavior when controllable variables of the process are modified. In processes such as performed in a chemical plant, the control variables relate to the chemical process under consideration such as water temperature and chemical flow rates. In a process such as a commercial or individual loan analysis system, the variables relate to economic considerations such as whether a bank reference is good or bad.
In prior art plant process control systems, plant experimentation programs have been used to find out what happens to a system when it is perturbed to allow characteristics which can lead to optimization to be discovered. Plant experimentation is a form of controlled interference used to learn more about the process without radically upsetting it. One approach to plant experimentation involves executing one or more sets of experiments in a limited amount of time to get process improvement information on selected sets of variables. The experimental case history is then analyzed using statistical analysis techniques such as a regression or correlation analysis to determine which variables significantly control a desired output such as yield. These prior art methods are very unwieldy in practice and result in an extended amount of time elapsing between the experiment and a determination to adjust the variables which control the desired output.